This invention relates to a battery charger, and particularly a pulse charger that is capable of controlling charging voltage by a counter and battery voltage feedback.
There are two battery types: primary (non-rechargeable) batteries and secondary (rechargeable) batteries. A primary battery must be discarded after a single use, which causes environmental pollution problems. Therefore, the secondary battery has become more widely used in newly developed technologies. In general, most secondary batteries nowadays can be recharged more than one thousand times. However, this is merely an average number without consideration of the time required for charging the battery and the charging methods, i.e., a good charger and proper battery utilization affect the performance of the secondary battery. Hence, it is necessary to have a proper charger with proper utilization while using a secondary battery.
The technique of properly charging a battery manually will not be described in the content of the following; instead, it will focus on battery chargers. In general, there are three considerations for a battery charger design: extended battery life, faster recharge time, and less circuit complexity. However, it is hard to take these three conditions into consideration at the same time in practical design. Therefore, some chargers emphasize faster charging capabilities (by using higher electric current) with simplified circuits, which shortens the battery life. Some chargers emphasize longer battery life with intelligent recharging design for circuits, but a longer time is necessary to charge a battery. To sum up, most chargers on the markets cannot simultaneously meet the requirements of the aforementioned considerations.
Hence, how to achieve a balance between the aforementioned three basic requirements to design a battery charger has become a heavily focused subject to RandD technicians.
In view of the above problems, the invention provides a pulse charger that maintains a secondary battery at full charge and has no chemical residue unconverted.
According to disclosed technique, the invention provides a kind of pulse charging method. It controls pulse output current of a charger to charge a secondary battery based on a voltage value of the secondary battery. It is characteristic of the charger to have a pulse output frequency that is in direct proportion to the voltage value of the secondary battery, and the time for outputting a pulse output frequency is always the same.
According to the above-mentioned method, the object of the invention is to provide a pulse charger which includes: an on/off switch connected a power supply and a secondary battery, for switching the connection of the power supply and of the secondary battery to generate a pulse output for charging the secondary battery; a counter control circuit that connects to the secondary battery to detect the voltage value of the secondary battery and is in direct proportion to the voltage value to generate a resonant frequency; and a switch control circuit that connects with the on/off switch and the counter control circuit receiving the resonant frequency output to control the switching rate of the on/off switch.
The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.